[QE-users] Output of post-processing pp.x for 1D plot of the pseudo charge density from individual orbitals

[Marin Luca]

Dear QE users,


I'm facing difficulties in interpreting the output of pp.x. I'm running a scf calculation on an isolated atom of Xe and a subsequent post-processing in order to plot the (pseudo) charge density coming from the individual atomic orbitals. I am running QE v6.4.1

By reading the manual of pp.x (PP/Doc/INPUT_PP.txt), I read that it should be possible to obtain a 1D plot (a simple x-y plot of a 1D function) of this charge density. I tried to do so with the following input file:


&INPUTPP
prefix = 'smoothy',
outdir = './smoothy/',
filplot = 'smoothy.dat',
plot_num = 7,
kpoint=1,
kband(1) = 1,
kband(2) = 18,
!lsign=.true.
/
&PLOT
filepp(1)= 'smoothy.dat'
weight(1) = 1.0

iflag=0
output_format = 0,

fileout = 'smoothy.plt'
e1(1) = 0.5,
e1(2) = 0.5,
e1(3) = 0.5,
x0(1) = 0,
x0(2) = 0,
x0(3) = 0,
nx = 800
/

in which my idea is to plot the charge density of each orbital along that line defined by the vectors e1 and x0.

The calculation finishes fine, but the output "plottable" files contain 3 columns (they look like this):

        0.0000000000       -0.0174697150        0.0000000000
        0.0012515645       -0.0174697013       -0.0000000007
        0.0025031289       -0.0174696330       -0.0000000036
        0.0037546934       -0.0174694282       -0.0000000101
        0.0050062578       -0.0174689508       -0.0000000216

and many other lines. While I sort of get that the first column is the spatial variable and the second should be the charge density (the |\psi|^2), I have no clue what the third column is.

Could anyone explain to me what the third column means and what I should plot in order to get the pseudo charge density as a function of this radial coordinate only? Moreover, even with lsign commented out, some values of the second column are negative which is very weird as this should be |\psi|^2. Do you also have an answer on this?

I thank you all in advance for your help and time!

Best wishes,
Luca


ETH Zurich
Luca Marin
Materials Theory
Department of Materials
HIT G 43.1
Wolfgang-Pauli-Strasse 27
8093 Zurich, Switzerland
phone +41 44 633 81 67
luca.marin at mat.ethz.ch<mailto:luca.marin at mat.ethz.ch>
https://www.theory.mat.ethz.ch<https://www.theory.mat.ethz.ch/>

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